1. Field of the Invention
The present invention relates to a technology pertaining to a suspension mechanism constituting part of the wheel suspension system of an automobile. More particularly, the present invention is concerned with a dust cover strike plate for providing a dust cover abutting face in an automobile suspension mechanism, and a suspension mechanism having the dust cover strike plate attached thereto.
2. Description of the Related Art
Automobile suspension mechanisms to date, as illustrated in FIG. 4, employ a shock absorber 12 composed of a cylinder 14 and a piston 16, which is installed on an automobile with the cylinder 14 mounted to a hub carrier or the like on the side of a wheel 10, and the piston rod 16 mounted to a body 11 of the automobile. One type of suspension mechanism known in the art is a suspension mechanism of strut or four-link design, having a coil spring 20 assembled fitting about the outside of the shock absorber 12, supported at its upper end by an upper spring support member 22 disposed on an upper support 18 or the body 11, and supported at its lower end by an annular disk-shaped lower spring support member 24 projecting from an outer circumferential surface of the cylinder 14, whereby biasing force of the coil spring 20 is exerted between the body 11 and a suspension arm 21, via the shock absorber 12.
This type of suspension mechanism is subjected to change in the mounting angle of the shock absorber 12 with respect to the body 11, due to displacement of the hub carrier in associating with pivotal motion of the suspension arm during driving of the automobile. It has been pointed out that, since at this time the point of application of external force exerted through the wheel 10 diverges from the center axis of the shock absorber 12, and since bending moment is produced in shock absorber 12 due to spring action of the upper support 18 and the like, there is a likelihood of adverse effects by this bending moment on operation and durability at portions of the piston 16 that slide against the cylinder 14, and the like.
To cope with this drawback, the conventional suspension mechanism, as shown in FIG. 4, employs a design wherein the lower spring support member 24, which projects from the cylinder 14 of the shock absorber 12 and supports the lower end of the coil spring 20, is inclined in one direction and eccentric with respect to a plane perpendicular to the center axis of the coil spring 20, so that the axis of the coil spring 20 is inclined relative to the center axis of the shock absorber 12. That is, by inclining the center axis of the coil spring in this way, the direction in which the biasing force of the coil spring 20 is applied during contraction of the shock absorber 12 is eccentric with respect to the center axis of the shock absorber 12, whereby the biasing force can be applied in a direction that cancels the bending moment exerted on the shock absorber 12 during contracting motion of the shock absorber 12 as described above.
As disclosed in Citation 1 (JP-B-3205480), a shock absorber typically has a dust cover that is attached thereto with the piston rod and cylinder upper portion being covered by the dust cover in order to prevent these from being splashed by mud, water, or the like, so that sliding portions of the piston rod are protected.
With suspension mechanisms of such conventional design, it is revealed that the dust cover attached exhibits exceedingly poor durability in some instances, and it is recognized that the dust cover is readily to crack, and when attached in a hanging fashion tends relatively quickly to experience splitting in the lengthwise medial portion, resulting in the problem of the lower portion falling off. Research conducted by the inventors regarding this phenomenon showed no particular problem with the materials or durability of the dust cover per se, which led to the conclusion that the reason must lie in some structural element of the suspension mechanism.                [Citation 1]        JP-B-3205480        [Citation 2]        JP-A-2000-6630        [Citation 3]        JP-U-62-13237        